1. Field of the Invention
The present invention relates to a method for producing contacts of electrical components, the contacts being suitable for flip-chip mounting--particularly of components operating with surface acoustic waves (SAW components)--wherein electrically conductive structures on a substrate are encapsulated tightly against environmental influences by means of a cover in the form of a cap. The cover is formed with cutouts accommodating component structures in regions thereof, and a window is formed in the cover in which the pads of the electrically conductive structures being disposed.
An earlier, commonly owned application No. 08/743,540 (German application P 44 15 411.9) describes an encapsulation for electronic components with a cap that seals component structures on a substrate. The cap is formed by a cover which is provided on the substrate and has cutouts accommodating component structures in regions thereof. Such an encapsulation protects the component structures against environmental influences, with the result that electronic components encapsulated in such a way can be used directly in further applications, without the need for a further housing.
As miniaturization advances, the aim is to produce components which take up a minimal housing volume and have a small structural height. Such requirements are imposed, for example, on the use of electronic components in smart cards, such as telephone cards or credit cards, for example. Components with an encapsulation according to the above-mentioned earlier patent application fulfill these requirements in an optimum manner. This is particularly true when they are realized in a configuration which is suitable for flip-chip mounting.
To date, components suitable for flip-chip mounting have been mounted in a housing, in particular a ceramic housing. Selectively solderable layers with bumps must thereby be provided on the terminal pads of the component system. This necessitates a series of process steps which are highly problematic in particular for SAW components because, owing to overlapping planar finger structures, the probability of short circuits increases.